1. Field of the Invention
The present invention relates to a thermally transcribing printer and an image forming apparatus, particularly relates to a thermally transcribing printer and an image forming apparatus provided with a roller shaft attached with a roller used at least for one of sheet charging and sheet discharging and a roller shaft drive gear.
2. Description of the Related Art
In a background art, there is known an image forming apparatus (recording apparatus) of a thermally transcribing printer or the like including a roller shaft attached with a roller used at least for one of sheet charging and sheet discharging and a roller shaft drive gear (refer to, for example, JP-UM-A-62-108624).
JP-UM-A-62-108624, mentioned above, discloses a recording apparatus in which at a portion of fitting a roller shaft attached with a platen (roller) for carrying sheet and a roller shaft drive gear, a pin inserting hole orthogonal to an axial direction is provided at the roller shaft, a pin is attached to the pin inserting hole, the pin is fitted with a groove both ends in a longitudinal direction of which are closed provided at a side face of the gear to thereby fix the roller shaft and a drive force transmitting portion of the roller shaft drive gear.
FIG. 11 is a perspective view showing a total constitution of a thermally transcribing printer according to an example of a background art. FIG. 12 is a sectional view showing a structure of attaching a roller shaft of the background art shown in FIG. 11. FIG. 13 is a perspective view showing a structure of attaching the roller shaft shown in FIG. 12 to a roller shaft drive gear. An explanation will be given of a structure of the thermally transcribing printer according to the example of the background art in reference to FIG. 11 through FIG. 13.
A shown by FIG. 11, a thermally transcribing printer apparatus of the background art includes a frame 101 made of a metal, a roller shaft 102 for charging sheet and discharging sheet, a roller shaft drive gear 103 made of a resin, a motor 104, a feeding roller 105, a motor bracket 106 made of a metal, a sheet bottom receiving guide 107, an ink sheet case 108, a plurality of middle gears 109, an ink sheet winding gear 110, and bearing members 120 and 121. The frame 101 is formed in a channel-like shape including one side face 101a and other side face 101b. Further, as shown by FIG. 12 and FIG. 13, a feeding roller 105 comprising rubber is mounted to a predetermined region at an outer peripheral portion of the roller shaft 102. Further, one end 102a of the roller shaft 102 is rotatably inserted into the bearing member 121 and is fitted to the roller shaft drive gear 103. As shown by FIG. 13, the one end 102 of the roller shaft 102 is worked in a D cut shape and is fitted to a fitting hole 103a in a D-like shape of the roller shaft drive gear 103. Thereby, the roller shaft 102 and the roller shaft drive gear 103 can be connected without being idly rotated. The motor 104 is attached to the motor bracket 106 and functions as a drive source for driving the roller shaft drive gear 103 and the ink sheet winding gear 110.
Next, an explanation will be given of sheet charging and sheet discharging operation of the thermally transcribing printer according to the example of the background art. According to the sheet charging and sheet discharging operation of the printer of the background art, as shown by FIG. 11, a drive force of the motor 104 is transmitted to the roller shaft drive gear 103 and the ink sheet winding gear 110 via the plurality of middle gears 109. At this occasion, the drive force is transmitted from the roller shaft drive gear 103 to the roller shaft 102. Thereby, the roller shaft 102 is rotated while being supported by the bearing members 120 and 121 and therefore, the feeding roller 105 is rotated. As a result, sheet (not illustrated) is carried in a sheet charging direction or a sheet discharging direction. Further, the drive force is also transmitted from the ink sheet winding gear 110 to an ink sheet winding roller shaft (not illustrated) and therefore, an ink sheet (not illustrated) is wound.
According to the thermally transcribing printer of the background art shown in FIG. 11 through FIG. 13, the roller shaft 102 and the roller shaft drive gear 103 are connected so as not to be rotated idly and therefore, it is necessary to form the D cut shape at the one end 102a of the roller shaft 102 by machining requiring a time period in working. Therefore, there is a problem that part cost is expensive. Further, when the roller shaft 102 is integrated to the frame 101 having the channel-like shape in an integrating step, the roller shaft 102 is inserted into an inserting hole of the bearing member 121 from a lateral direction and therefore, integration operability is poor, as a result, there poses a problem that the integrating step is complicated.
Further, according to the structure disclosed in JP-UM-A-62-108624, mentioned above, it is necessary to provide the pin inserting hole in the direction orthogonal to the axial direction of the roller shaft and therefore, there poses a problem that a time period is taken in working to bore the roller shaft. Further, the pin is inserted into the roller shaft in an integrating step and therefore, there poses a problem that integration operability is poor.